Bill Mueller wrote on Fri, 10 October 2008 16:41 |
what I meant was to take an ITB mix, route it both to the two buss and split it to a level matched analog summing console. Then record the outputs from both back to the DAW and compare them. I'm not talking about using an SSL with outboard reverbs and trying to match an ITB mix.
From what I gather, this has been done already and I missed it or did not have time to look into it. If anyone has any more info about these kinds of tests, I would appreciate it and might actually have time now to listen to the results. I don't believe I have a dog in this fight, because of the rig I use, but I often wonder if a dedicated digital console like mine and PT or MX rig constitute ITB? Personally, I doubt it, because I am spreading the processing load across double the processing capacity with the digital console.
Thanks,
Bill
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Hi Bill,
some years ago when the dangerous 2 Bus first appeared on the market my technician Manni and I were asked to perform the requested summing test for a German studio magazine.
Test 1
We used a Pro Tools session recorded in Abbey Road 1 performed by The Royal Philharmonic Orchestra. We simply used the monitor mix of the recording engineer and tried to copy the volumes and panning on three different analogue summing boxes or consoles.
First we bounced a 1 Khz sine wave and copied it to each track in the Pro Tools session. Then we soloed each track with the sine wave and measured the levels on each side of the master with the waves PAZ meter. The next step was to send the tones out of 16 individual outputs of Apogee 16x DA converters to the summing boxes and send the stereo output back through Apogee AD converters to a Pro Tools stereo track. We adjusted the master level control of the summing box until the PAZ meter on the input channel showed the same levels as in the original session. We had to fine tune some of the Apogee's output levels with the Dangerous 2 Bus. That was of coarse much easier with the console 's faders.
One was my 1976 Helios console and the other a simple passive mixer that Manni had built for this session with stereo faders used as symmetrical faders directly connected to a discrete symmetrical summing stage via summing resistors and left and right switches. The purest mixing board I have heard so far.
Each mix was clearly sounding different from each of the others while all of the three analogue mixes had one aspect in common. The dynamic was significantly different from the digital mix. That was not only easy to hear but also easily measurable. I told the founders of Logic about our test and they came to my studio with their top development engineers and after they had heard the mixes they asked me for the files.
Beside the aesthetic differences which are obviously a matter of taste there were those dynamical differences:
The Pro Tools mix showed the lowest levels and the highest peaks. It was the most dynamic mix regarding the difference between the quietest and the loudest signal.
But the analogue mixes sounded louder. Obviously all of the analogue mixes looked and sounded slightly compressed in the quiet parts. Consequently reverb tails of the majestic Abbey Road 1 hall seemed to be more detailed in the analogue mixes.
In addition the waveforms looked as if there was a peak limiter on the loudest fast percussive signals.
That is especially funny because marketing people of analogue summing devices obviously love to praise the extra headroom of their boxes. It seemed to us that they mix it up with compression.
The most dynamic analogue mix most similar to the Pro Tools mix came out of Manni's Mixer.
However while the pp parts sounded as if they were brought up by a compressor in the analogue mixes, the ff parts sounded as if somebody pushed the master fader up and the Pro Tools Mix sounded thinner in these parts. The ff parts were clearly louder in the analogue mixes and that's what the waveforms showed.
We had the impression that the Pro Tools mix engine was not able to sum all tracks
to their full dynamic level while the peaks were still higher. Listening to the main mics (decca tree with 3 M50 ) in solo however showed this dynamic.
The analogue mixes sounded more satisfying to all of us, rockers and classical Tonmeisters. A master compressor, a peak limiter a slight broad lift in the lower midrange and riding the levels at the ff-parts brought the Pro tools miy closer to the analogue mixes.
I am not saying which mix was closer to truth.